Revision as of 15:54, 15 April 2009

An SGI Octane2 (2000-2004)

An SGI Octane (1997-2000)

The SGI Octane (and the very similar SGI Octane2) are UNIX workstations marketed by SGI. Both are SMP-capable (up to 2 identical processors) workstations, originally based on the MIPS architecture R10000 processor. Newer Octanes are based on MIPS R12000 and R14000. Octane2 has four improvements compared to Octane. Octane2 has revised power supply, system-board and xbow. Octane2 also shipped with VPro graphics and supports all available VPro cards (V6, V8, V10 and V12). Later revision Octanes also included some of the improvements mentioned. The machines shared a codename "Racer" or "Speedracer" inside SGI.

The Octane was the direct successor to the SGI Indigo2, and itself was succeeded by the SGI Tezro, and its immediate sibling is the SGI O2. SGI withdrew the Octane2 from the price book on May 26 2004, and ceased Octane2 production on June 25th, 2004. Support for the Octane2 will be withdrawn in June 2009.

System architecture overview

The Octane's system-board is designated as IP30. The system is based on SGI's Xtalk architecture. This means it does not use a system bus; instead it has a router Xbow that connects any two of its ports. One of the ports is used for the processor and memory subsystem, one is available for PCI (actually PCI-64) expansion and four are XIO slots (packet-based high-bandwidth bus, somewhat similar to HyperTransport). This makes it very similar to a single node of the SGI Origin 200 system.

The XIO is here and there bridged to PCI-64, using a chip named BRIDGE. The places where it happens include the system board (for the IOC3 multi-I/O chip, two ISP1040B SCSI controllers and RAD1 audio), MENET cards (four IOC3s) and the PCI cage (used for PCI cards in Octane). ARCS is provided as the boot firmware, similar to all contemporary SGI computer systems.

Processors overview

Here's a table of processors that have been available for Octane series.

Processor:

Cache:

Single (MHz):

Dual (MHz):

R10000SC

1MB

175, 195, 225, 250

175, 195, 225, 250

R12000SC

2MB

270, 300, 400

270, 300, 400

R12000SCA

2MB

360, 400

360, 400

R14000SCA

2MB

550, 600

550, 600

The Octane series has single and dual CPU modules. You cannot add a second CPU, so the only option is to replace the whole CPU module.

Memory subsystem

The Octane allows 256 MB to 8 GB of system memory, using proprietary 200-pin DIMMs. There are two system board revisions. The first revision (part number 030-0887-00x, usually distinguished by a black handle) only supports 2GB of RAM while the later one (part number 030-1467-001, with a silver handle) supports up to 8GB. The -0887 revision of the mainboard will work with all 32-128 MB DIMMS and the stacked variant of 256MB DIMMS, but not the later single-board version (SGI P/N 9010036). The memory subsystem has vast reserves of bandwidth that can be directly served by the Xbow router to any XIO card.

The Octane's memory controller is aptly named HEART. It acts as a controller between the processor, the memory (SDRAM) and the XIO bus.

Graphics subsystem

Graphics on the Octane are provided by a series of cards: SI, SI+T, SSI, MXI. These are updated XIO versions of Solid Impact (SI), High Impact (SI+T) and Maximum Impact (MXI) from the SGI Indigo2 that were internally designated by SGI as 'MARDIGRAS'. The boards were accelerated and reengineered with faster geometry engine and texture modules to create their new versions: SE, SE+T, SSE, MXE. The SI/SE provides 13.5MB of framebuffer memory while the SSE and MXE have a 27MB framebuffer. The '+T' indicates an additional high speed RDRAM texture board which gives 4MB of texture memory, which is practically indispensable, though quite expensive and fragile. The SI/SE+T has one texture board while the MXI/MXE has 2 texture boards, however, the 2 boards in the MXI/MXE do not double the available texture memory to the system. It just doubles the texture performance.

Later Octanes and Octane2s support the SGI VPro graphics board series, designated 'ODYSSEY'. The first VPro series cards were the V6 and V8. The main differentiator being that the V6 has 32MB of RAM (unlike the MARDI GRAS option, framebuffer memory and texture memory come from the same pool) and V8 having 128MB. Later, the V10 (32MB) and V12 (128MB) were introduced. The main difference with the new VPro V10/V12 series is that they had double the geometry performance of the older V6/V8. V6 and V10 can have up to 8MB RAM allocated to textures (2X more than the textured-enabled MARDIGRAS options), while V8 and V12 can have up to 108MB RAM used for textures.

The VPro graphics subsystem consists of an SGI proprietary chip set and associated software. The chip set consists of the buzz ASIC, pixel blaster and jammer (PB&J) ASIC, and associated SDRAM.

The buzz ASIC is a single-chip graphics pipeline. It operates at 251 MHz and contains on-chip SRAM. The buzz ASIC has three interfaces:

Host (16-bit, 400-MHz peer-to-peer XIO link)

SDRAM (The SDRAM is 32 MB (V6 or V10) or 128 MB (V8 or V12); the memory bus operates at half the speed of the buzz ASIC.)

PB&J ASIC

As with the MARDIGRAS boards, all VPro boards support OpenGL in hardware (MARDIGRAS is OpenGL 1.1 + SGI Extensions, while VPro upgraded support to OpenGL 1.2) and OpenGL ARB imaging extensions, allowing for hardware acceleration of numerous imaging operations at real-time rates.

Audio subsystem

Audio hardware is standard; even without extensions they can support low-latency (3 ms input-to-output) audio streams. Alesis ADAT 8-channel, 24-bit optical ports are built-in, along with S/PDIF or AES/EBU optical and coaxial ports. This makes the Octane into a respectable digital audio workstation.

Case and expandability

The Octane cases are large (WxHxD: 30x40x35 cm) and heavy (25 kg), yet there are no internal 5.25" drive bays, so external CD-ROM drives must be connected if desired. Extensions include video I/O, audio I/O, networking, realtime video compression boards, and external storage options (through SCSI, Fibre-Channel or Firewire). Octanes can use standard PCI cards with optional PCI cardcage aka 'shoebox' (which provides 2-full length and 1 half-length 5V PCI-64 slots), or a PCI to XIO adaptor (known as a 'shoehorn' which provides a single 3.3/5V 64-bit PCI slot). Older Octanes can be upgraded with VPro graphics. The official statement from Silicon Graphics is that V10 and V12 graphics board require a xbow revision 1.4 and Cherokee power supply. VPro V6 and V8 require a Cherokee power supply; any xbow revision will work. However, users in the field have found that any version of VPro graphics will work with any power supply and frontplane. There's an easy way to (usually) identify the difference between Cherokee (747 watt) and older Lucent (623 watt) power supplies. The mounting handle is silver on the Cherokee International manufactured power supplies while the original Lucent manufactured ones have black handles. Unfortunately, the handles can become damaged and are very easy to replace, not necessarily with the original color. Caveat emptor.

Single-cpu Octanes and Octane2's can be upgraded to dual-cpu models by replacing the complete cpu module. Again, the official statements are that certain mainboards are required for certain cpu modules but this doesn't appear to generally hold up in the real world. Perhaps the SGI stated requirements came from early revisions of the relevant parts but no one in the hobbyist or reseller communities has yet reported a case where the official requirements were accurate.

Octane skins come in three types. The original Octane has green skins with the original 'cube' logo. The later model Octanes have skins the same colour as the original but with Octane2-style lettering and logos. Octane2 systems have blue skins with the current 'sgi' logo.

I/O subsystem

Octane series supports Ultra Wide SCSI devices and has two SCSI controllers. System can have up to three internal 3.5" SCSI SCA devices. Octanes use special mounting sleds for the harddrives which are compatible with Origin 2000, Origin 200 and Onyx 2. The system also has external Ultra Wide SCSI bus.

Available Operating Systems

The SGI Octane with IMPACT-class graphics was first supported by IRIX version 6.4. VPro-class graphics have been supported since IRIX version 6.5.10 for V6 and V8, with V10 and V12 graphics supported as of 6.5.11 (or 6.5.10 with a special driver patch).

Linux runs on the Octane series, although the patch is quite experimental. Link to Linux/MIPS 2.6.12 kernel patch is available in the External Links section of the page. Both graphics versions are supported, and X Window System is available on the ImpactSR series.

Parts compatibility between Octane and Octane2

Octane2 consists of different revisions of the Octane components, specifically a higher-wattage power supply, Xbow revision 1.4 in the frontplane, and an updated IP30 (part number 030-1467-XXX) The updated IP30 allows the use of higher-density memory modules (up to 8GB total RAM). The single-board 256MB DIMMs will not work in the older 030-0887-XXX mainboards, neither will the 512MB modules or any 1GB module.